SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc67ad4002552001dd40476dfc46d42c009f007f26f16bd1e43825d7c4336a23' 
  AND token = 'JaGVQiOWXQ5jzW7qnvZOjflDRaVt/CUREKM506AWvSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}